Project Finds Fish Prefer Natural Shorelines

The U.S. benefits from a wealth of resources and activities that depend on healthy coastal habitats. However, these habitats are being degraded by extensive hardening of shorelines due to climate-driven sea level rise, increasing shoreline development, land use changes in coastal watersheds, pollution, and invasions of non-native species. In the Mid-Atlantic region alone, coastal development has been intense along the Chesapeake Bay and the Delmarva Coastal Bays, threatening important habitats such as wetlands and seagrass beds. Up to 80% of shoreline in some Chesapeake Bay tributaries has become “hardened” with bulkheads and riprap (structures made of different kinds of rock or rubble).

With a five-year, multi-million dollar study, NCCOS supports the Smithsonian Institution Environmental Research Center and six other universities, institutions and agencies in the region to quantatively evaluate how altered shorelines affect life in coastal bays of Delaware, Maryland and Virginia. The project, at mid-point, is producing important results. Comparing six shoreline habitat types (bulkhead, riprap, rip-rap-sill, sandy beach, invasive Phragmites reed, and native Spartina cordgrass) preliminary findings show reduced fish densities, lower dissolved oxygen levels, and reduced egg laying at the hardened shorelines compared to the “living” shorelines. This research has important implications regarding the future health of our nation’s coastal habitats and resources in the face of management actions to counter sea level rise.